Self-supporting structures having active materials

ABSTRACT

A method and system for manufacturing and using a self-supporting structure in processing unit for adsorption or catalytic processes. The self-supporting structure has greater than 50% by weight of the active material in the self-supporting structure to provide an open-celled structure providing access to the active material. The self-supporting structures, which may be disposed in a processing unit, may be used in swing adsorption processes and other processes to enhance the recovery of hydrocarbons.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/437,327 titled “Self-Supporting Structures Having ActiveMaterials,” filed on Dec. 21, 2016, and U.S. Provisional PatentApplication No. 62/585,574 titled “Self-Supporting Structures HavingActive Materials,” filed on Nov. 14, 2017, having common inventors andassignee, the disclosure of which is incorporated by reference herein inits entirety.

This application is related to U.S. Provisional Patent Application No.62/437,319 titled “Self-Supporting Structures Having Active Materials,”filed on Dec. 21, 2016, the disclosure of which is incorporated byreference herein in its entirety.

FIELD

The present techniques relate to fabrication of self-supportingstructures being open-celled and including active material. Inparticular, the self-supporting structures may be used in separationand/or catalysis processes, such as swing adsorption processes and otherprocesses to enhance the recovery of hydrocarbons.

BACKGROUND

Processing techniques are useful in many industries and can typically beaccomplished by flowing a mixture of fluids over an active material,such as a catalyst or adsorbent material, to provide the preferredproduct stream. For adsorption process, the adsorbent materialspreferentially adsorbs one or more gas components, while not adsorbingone or more other gas components. The non-adsorbed components arerecovered as a separate product. For catalytic processes, the catalystis configured to interact with the components in the stream to increasethe rate of a chemical reaction.

By way of example, one particular type of gas separation technology isswing adsorption, such as temperature swing adsorption (TSA), pressureswing adsorption (PSA), partial pressure purge swing adsorption (PPSA),rapid cycle pressure swing adsorption (RCPSA), rapid cycle partialpressure swing adsorption (RCPPSA), and not limited to but alsocombinations of the fore mentioned processes, such as pressure andtemperature swing adsorption. As an example, PSA processes rely on thephenomenon of gases being more readily adsorbed within the porestructure or free volume of an active material, such as an adsorbentmaterial, when the gas is under pressure. That is, the higher the gaspressure, the greater the amount of readily-adsorbed gas adsorbed. Whenthe pressure is reduced, the adsorbed component is released, or desorbedfrom the adsorbent material.

The swing adsorption processes (e.g., PSA and TSA) may be used toseparate gases of a gas mixture because different gases tend to fill themicropore of the adsorbent material to different extents. For example,if a gas mixture, such as natural gas, is passed under pressure througha vessel containing an adsorbent material that is more selective towardscarbon dioxide than it is for methane, at least a portion of the carbondioxide is selectively adsorbed by the adsorbent material, and the gasexiting the vessel is enriched in methane. When the adsorbent materialreaches the end of its capacity to adsorb carbon dioxide, it isregenerated in a PSA process, for example, by reducing the pressure,thereby releasing the adsorbed carbon dioxide. The adsorbent material isthen typically purged and repressurized. Then, the adsorbent material isready for another adsorption cycle.

Typically, the structures used in catalytic processes and adsorptionprocesses have a limited array of physical structure types. The activematerial are often structured into beads, granules, spheres or pelletsusing binders and processing techniques like extrusion or spray drying.The beads, granules, spheres or pellets are then packed together withina unit as a packed bed for the catalytic or adsorption processes. As aresult, the conventional fabrication of catalysts or adsorbents, involveextrusions of small sphere-like active materials to be used in packedbeds (e.g., spheres, pellets, lobes, etc.). However, the packed bedsprovide tortuous paths through the packed bed, which result in largepressure drops.

In other configurations, the structure may be an engineered structure,such as a monolith. In engineered structures, the active materials arecoated onto substrates, such as a metal or ceramic monolith. Theengineered structures provide substantially uniform flow paths, whichlessen pressure drops as compared to packed beds. However, with thesestructures the majority of weight is inactive material that is used toform the underlying support structure.

As a result, typical fabrication approaches of structures involveextrusions of small sphere-like active materials to be used in packedbeds (e.g., spheres, pellets, lobes, etc.), or the application of thincoatings of active material on monolith substrates (e.g., ceramic ormetal monoliths). The packed beds have large pressure drops as comparedwith engineered structures. Also, the engineered structures includeadditional weight from structural support that is inactive material,which increases the size and weight of the structure.

Accordingly, there remains a need in the industry for apparatus,methods, and systems that provide enhancements in processes havingself-supporting structures that include active materials and may includecomplex geometries. Further, the present techniques provide enhancementsby integrating self-supporting open-celled structures with adsorption orcatalytic processes, such as swing adsorption processes to separatecontaminants from a feed stream. Accordingly, the present techniquesovercome the drawbacks of conventional structures in separation and/orcatalysis processes.

SUMMARY OF THE INVENTION

In one embodiment, a processing unit is described. The processing unitincludes a housing forming an interior region; a self-supportingstructure disposed within the interior region, wherein theself-supporting structure has greater than 50% by weight of the activematerial in the self-supporting structure, wherein the self-supportingstructure is an open-celled structure configured to provide one or moredefined channels for fluid flow paths through the self-supportingstructure; and a plurality of valves secured to the housing, whereineach of the plurality of valves is configured to control fluid flowalong a flow path extending between the self-supporting structure and alocation external to the housing.

In one or more embodiment, the processing unit may include variousenhancements. For example, the processing unit may include two or moreof the plurality of valves are operated via common actuation mechanism;the processing unit may be a cyclical swing adsorbent bed unitconfigured to remove contaminants from a gaseous feed stream that passesthrough the self-supporting structure; the self-supporting structure mayhave greater than 60% by weight of the active material in theself-supporting structure or the self-supporting structure may havegreater than 70% by weight of the active material in the self-supportingstructure; the self-supporting structure may have an inert supportmember (e.g., inorganic or inactive support member) coated by the activematerial in the self-supporting structure (e.g., inert with respect tothe stream passing through the self-supporting structure or inert atoperating conditions); may include a flow distributor disposed betweenthe adsorbent bed and the plurality of valves; the housing may beconfigured to maintain a pressure from 5 pounds per square inch absolute(psia) and 1,400 psia; the self-supporting structure may have a layer ofactive material that is greater than 10 micrometers or may have a layerof active material that is greater than 100 micrometers; wherein the oneor more defined channels comprise two or more channels that aresubstantially parallel and/or the self-supporting structure has a lowthermal mass.

In yet another embodiment, a method for removing contaminants from afeed stream is described. The method comprises: a) performing one ormore adsorption steps in an adsorbent bed unit, wherein each of the oneor more adsorption steps comprise: passing a gaseous feed stream throughthe self-supporting structure disposed in an interior region of ahousing of the adsorbent bed unit to remove one or more contaminantsfrom the gaseous feed stream, wherein the self-supporting structure hasgreater than 50% by weight of the active material in the self-supportingstructure, wherein the self-supporting structure is an open-celledstructure configured to provide one or more defined channels for fluidflow paths through the self-supporting structure; b) performing one ormore regeneration steps, wherein each of the one or more regenerationsteps comprise conducting away at least a portion of the one or morecontaminants in a contaminant output stream; and c) repeating the stepsa) to b) for at least one additional cycle.

Further, in one or more embodiment, the method for removing contaminantsfrom a feed stream may include various enhancements. For example, themethod may be a swing adsorption method and the cycle duration may befor a period greater than 1 second and less than 600 seconds or a periodgreater than 1 second and less than 300 seconds; wherein the performingone or more regeneration steps comprises performing one or more purgesteps, wherein each of the one or more purge steps comprise passing apurge stream through the self-supporting structure to conduct away atleast a portion of the one or more contaminants in the contaminantoutput stream; wherein the gaseous feed stream may be a hydrocarboncontaining stream having greater than one volume percent hydrocarbonsbased on the total volume of the gaseous feed stream; wherein a feedpressure of the gaseous feed stream may be in the range between 400pounds per square inch absolute (psia) and 1,400 psia; whereinperforming the one or more adsorption steps may be configured to lowerthe carbon dioxide (CO₂) level to less than 50 parts per million volume;wherein performing the one or more adsorption steps may be configured tolower the water (H₂O) level to less than 105 parts per million volume;and/or the self-supporting structure has a low thermal mass.

In yet another embodiment, a method of manufacturing a processing unitis described. The method may include: creating a template for aself-supporting structure; disposing a mixture within the template,wherein the mixture has greater than 50% by weight of the activematerial in the self-supporting structure and the remaining mixtureincludes binder material; curing the template and the mixture to form aself-supporting structure that is maintains a solid form; removing thetemplate from the self-supporting structure, wherein the self-supportingstructure is an open-celled structure configured to provide one or moredefined channels for fluid flow paths through the self-supportingstructure based on the template; and disposing the self-supportingstructure within housing of a processing unit having an interior region.

Moreover, in one or more embodiment, the method of manufacturing aprocessing unit may include various enhancements. For example, themethod may include creating a three-dimensional model of theself-supporting structure having predetermined geometries for one ormore defined channels in the through the self-supporting structure; mayinclude creating a model of a template based on the three-dimensionalmodel of the self-supporting structure; may include printing athree-dimensional template based on the model of the template; whereinremoving the template from the self-supporting structure may furthercomprise heating the self-supporting structure and the template to meltor decompose the template and conduct away the melted template; mayinclude vibrating the template and the mixture prior to curing thetemplate and mixture to lessen any voids that may be formed between thetemplate and mixture; wherein curing the template and the mixture mayfurther comprise sintering the binder material and active material intoa cohesive solid structure that is the self-supporting structure; and/ormay include creating a plurality of valve ports into the housing; andsecuring a valve to the housing in each of the plurality of valve portsto form a plurality of valves, wherein each of the plurality of valvesis configured to control fluid flow between the self-supportingstructure and a location external to the housing.

Further still, in yet another embodiment, a method of manufacturing aprocessing unit is described. The method comprises: extruding a mixtureinto a monolith form comprising a plurality of substantially parallelchannels, separated by thin walls, wherein the mixture has greater than50% by weight of the active material in the self-supporting structureand the remaining mixture includes binder material; drying the monolithform; and calcining the monolith form from 400° C. to 800° C. to form amechanically stable, active monolith form; wherein the plurality ofsubstantially parallel channels have a cross sectional shape of asquare, a circle, a triangular, or a hexagonal; wherein the cell densityof the monolith form is in a range between 200 cells per square inch and2,000 cells per square inch; and wherein the walls separating theplurality of substantially parallel channels have a thickness in therange between 40 micron to 1 millimeter.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other advantages of the present disclosure may becomeapparent upon reviewing the following detailed description and drawingsof non-limiting examples of embodiments.

FIG. 1 is a flow diagram of a method for fabricating and using aself-supporting structure in accordance with an embodiment of thepresent techniques.

FIGS. 2A, 2B and 2C are various diagrams of a mold, combined mold andmixture and resulting self-supporting structure in accordance with anembodiment of the present techniques.

FIGS. 3A, 3B and 3C are various diagrams of a mold, combined mold andmixture and resulting self-supporting structure in accordance withanother embodiment of the present techniques.

FIGS. 4A, 4B and 4C are various diagrams of a mold, combined mold andmixture and resulting self-supporting structure in accordance with yetanother embodiment of the present techniques.

FIGS. 5A and 5B are various diagrams of a combined mold and mixture andresulting self-supporting structure in accordance with still yet anotherembodiment of the present techniques.

FIGS. 6A and 6B are various diagrams of a mold and a self-supportingstructure in accordance with another embodiment of the presenttechniques.

FIGS. 7A and 7B are various diagrams of two monolith structures inaccordance with an embodiment of the present techniques.

FIG. 8 is an exemplary diagram of an x-ray diffraction scan of theself-supporting structure.

FIG. 9 is an exemplary SEM diagram of a self-supporting structure.

FIGS. 10A and 10B are exemplary SEM diagrams of a self-supportingstructure.

FIG. 11 is an exemplary diagram of overlay patterns that match 5Azeolites.

FIG. 12 is a diagram of the weight loss for 3A, due to loss of adsorbedwater, as a function of temperature.

FIGS. 13A to 13D are diagrams of various profiles.

FIG. 14 is an exemplary diagram of self-supporting structure monolithtesting.

FIGS. 15A and 15B are exemplary diagrams of polyethylene spheres used inself-supporting structure monoliths.

FIGS. 16A to 16D are exemplary diagrams of a permeance measurements inaccordance with an embodiment of the present techniques.

FIG. 17 is an exemplary diagram of average pore diameter based on gaspermeance measurements in accordance with an embodiment of the presenttechniques.

FIG. 18 is an exemplary diagram of water breakthrough in accordance withan embodiment of the present techniques.

FIG. 19 is a three-dimensional diagram of the swing adsorption systemwith six adsorbent bed units and interconnecting piping in accordancewith an embodiment of the present techniques.

DETAILED DESCRIPTION OF THE INVENTION

Unless otherwise explained, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which this disclosure pertains. The singular terms“a,” “an,” and “the” include plural referents unless the context clearlyindicates otherwise. Similarly, the word “or” is intended to include“and” unless the context clearly indicates otherwise. The term“includes” means “comprises.” All patents and publications mentionedherein are incorporated by reference in their entirety, unless otherwiseindicated. In case of conflict as to the meaning of a term or phrase,the present specification, including explanations of terms, control.Directional terms, such as “upper,” “lower,” “top,” “bottom,” “front,”“back,” “vertical,” and “horizontal,” are used herein to express andclarify the relationship between various elements. It should beunderstood that such terms do not denote absolute orientation (e.g., a“vertical” component can become horizontal by rotating the device). Thematerials, methods, and examples recited herein are illustrative onlyand not intended to be limiting.

As used herein, “majority component” means greater than 50% by weight.

As used herein, “open-celled” refers to structures having open channelnetworks, compared to extruded solid shapes, such as spheres or pellets.The open-celled structures include monoliths or other engineeredstructures that provide flow paths through channels or passages in therespective structure.

As used herein, “stream” refers to a fluid (e.g., solids, liquid and/orgas) being conducted through various equipment. The equipment mayinclude conduits, vessels, manifolds, units or other suitable devices.

As used herein, volume percent is based on standard conditions. Thestandard conditions for a method may be normalized to the temperature of0° C. (e.g., 32° F.) and absolute pressure of 100 kiloPascals (kPa) (1bar).

The present techniques relate to the fabrication of self-supportingstructures from active material, which may have complex geometries andbe open-celled structures. In particular, the present techniques relateto enhancements in the self-supporting structures that contain amajority of active material (e.g., greater than 50% by weight or greaterthan or equal to 60% by weight) to provide enhanced structures. Theenhanced structures may provide flexibility through customizableconfigurations, which may enhance the flow paths and provide highervolumetric efficiency in the configurations, which are lighter thanconventional structures. The self-supporting structures may beconfigured to have various defined channels to provide fluid flow pathsthrough the structure.

The self-supporting structures may be useful in various chemical andengineering applications. The self-supporting structures of activematerial may be referred to engineered into various geometricstructures. By way of example, certain methods may be enhanced with theactive materials, such as adsorption and catalytic processes. Inparticular, a self-supporting structure may be used instead of a packedadsorbent bed, which have higher pressure drops and slower mass transferrates. In the packed bed configurations, the pressure drops and masstransfer limitations do not permit or are inefficient in operating theadsorption or catalytic processes at rapid cycles. Further, large volumegas separation processes, which rely upon pressure swing adsorption andrapid cycling, involve self-supporting structures with low pressure dropand high volumetric efficiency. The present techniques may provideenhancements to the associated structures to enhance the respectivemethod and associated economics.

The self-supporting structure may be fabricated from various techniques,such as intrusion and extrusion techniques. For example, the techniquesmay include intrusion processes that employs three-dimensional (3D)printing. The 3D printing approach may use templates to produce customstructures of active material (e.g., a zeolite) that is combined with abinder material. By using the templates, the self-supporting structuremay be formed into complex geometries, which may be an open-celledstructure configured to provide defined channels for fluid flow pathsthrough the structure. As another example, an extrusion method may beemployed to produce monolith structures composed of the active materialcombined with the binder material. Both fabrication methods may utilizeactive materials, such as active inorganic materials, that are stable tohigh temperature calcinations (e.g., equal to or greater than 500° C.)and combination of organic and inorganic binders.

By way of example, the present techniques may also utilize 3D printingtechniques to design and produce custom self-supporting structures madeof active materials. The use of 3D printing and intrusion methodsprovide geometric flexibility in the design of structures that may notbe made using conventional extrusion methods. These structures may forman open-celled structures, which are configured to provide definedchannels for fluid flow paths through the respective structure. Further,engineering flexibility in the adsorbent material structures is alsoprovided, which removes the use and reliance on a ceramic or metalsubstrate, which lessen the cost of fabricating the self-supportingstructures, such as adsorbent beds.

The present techniques may also include an extrusion method to producebulk monolith structures, which have the active material as the majoritycomponent. In contrast, conventional techniques involve applying a thincoating of active material to an inactive substrate, such as an inertceramic or metal monolith substrates. The inactive substrate, whichtypically provides mechanical support for the thin coating of activematerial, is more than 90% of the total weight of the self-supportingstructure. Accordingly, the thin coating of active material inconventional self-supporting structures equal to or less than 10% of thetotal weight of the self-supporting structure.

In certain configurations, the self-supporting structure may includedifferent combinations of active material and binder material. Forexample, the self-supporting structure may be fabricated from amicroporous zeolites, which may be the active material. In certainconfigurations, the active material may be greater than or equal to 25%by weight of the self-supporting structure; greater than or equal to 40%by weight of the self-supporting structure; greater than or equal to 50%by weight of the self-supporting structure; greater than or equal to 60%by weight of the self-supporting structure; or greater than or equal to70% by weight of the self-supporting structure; while the remainingportion may include binder material. In other configurations, the bindermaterial may be less than 75% by weight of the self-supportingstructure; less than 60% by weight of the self-supporting structure;less than 50% by weight of the self-supporting structure; less than 40%by weight of the self-supporting structure; or less than 30% by weightof the self-supporting structure; while the remaining portion mayinclude active material.

The self-supporting structure may include higher masses of activematerial per unit volume that is greater than conventional coatingtechniques. For example, the layer or thickness of active material thatis greater than 10 micrometers, is greater than 100 micrometers or isgreater than 200 micrometers.

The active materials may include one or more adsorbent materials incertain configurations to adsorb contaminants from the stream. By way ofexample, the active materials may include zeolites, aluminophosphatemolecular sieves (e.g., AlPOs and SAPOs), ZIFs (zeolitic imidazolateframeworks (e.g., ZIF-7, ZIF-9, ZIF-8, ZIF-11, etc.) and carbons, aswell as mesoporous materials, such as the amine functionalized MCMmaterials, SBA, KIT materials. Other example of active materials mayinclude cationic zeolites, amine-functionalized mesoporous materials,stannosilicates, and/or carbons. In other configurations, the adsorbentmaterials may include zeolite type A (e.g., LTA structures), such as 3A,4A, 5A and/or 13X (which are highly porous adsorbents that have a highaffinity and high capacity to adsorb water, as well as other moleculesthat have dimensions small enough to fit into the uniform pores of thesestructures), 8-member ring zeolite materials (e.g., ZSM 58 and/or DDR).

In other configurations, the active material may include one or morecatalytic materials that are configured to react with the components inthe stream.

In addition, various enhancements in macro-pore engineering may be usedto provide additional pores and porosity. In particular, polymer spheresmay be added to the composition, which may be diminished or removed(e.g., a material that may be burn out) when calcination process isperformed on the composition. These polymer spheres may be used toincrease the system porosity and enhance the diffusional performance.

The binder materials may include organic and inorganic binders. Theorganic binder may include, for example, 2% aqueous solution of methylcellulose derivatives. The inorganic binder material may include, forexample, Si0₂ and/or clays. Silica particle diameter may be in the rangebetween 25 nanometer and 1,000 nanometer and silica particles in astring of pearls configuration.

By way of example, a processing unit may include a housing forming aninterior region; a self-supporting structure disposed within theinterior region, wherein the self-supporting structure has greater than50% by weight of the active material in the self-supporting structure,wherein the self-supporting structure is an open-celled structureconfigured to provide one or more defined channels for fluid flow pathsthrough the self-supporting structure; and a plurality of valves securedto the housing, wherein each of the plurality of valves is configured tocontrol fluid flow along a flow path extending between theself-supporting structure and a location external to the housing. Invarious configurations, the processing unit may include two or more ofthe plurality of valves are operated via common actuation mechanism; theprocessing unit may be a cyclical swing adsorbent bed unit configured toremove contaminants from a gaseous feed stream that passes through theself-supporting structure; the self-supporting structure may havegreater than 60% by weight of the active material in the self-supportingstructure or the self-supporting structure may have greater than 70% byweight of the active material in the self-supporting structure; theself-supporting structure may have a support member coated by the activematerial in the self-supporting structure, for example, a washcoatedceramic or metal structure; may include a flow distributor disposedbetween the adsorbent bed and the plurality of valves; the housing maybe configured to maintain a pressure from 5 pounds per square inchabsolute (psia) and 1,400 psia; the self-supporting structure may have alayer of active material that is greater than 10 micrometers or may havea layer of active material that is greater than 100 micrometers; whereinthe one or more defined channels comprise two or more channels that aresubstantially parallel and/or the self-supporting structure has a lowthermal mass.

As yet another example, a method for removing contaminants from a feedstream may include: a) performing one or more adsorption steps in anadsorbent bed unit, wherein each of the one or more adsorption stepscomprise: passing a gaseous feed stream through the self-supportingstructure disposed in an interior region of a housing of the adsorbentbed unit to remove one or more contaminants from the gaseous feedstream, wherein the self-supporting structure has greater than 50% byweight of the active material in the self-supporting structure, whereinthe self-supporting structure is an open-celled structure configured toprovide one or more defined channels for fluid flow paths through theself-supporting structure; b) performing one or more regeneration steps,wherein each of the one or more regeneration steps comprise conductingaway at least a portion of the one or more contaminants in a contaminantoutput stream; and c) repeating the steps a) to b) for at least oneadditional cycle. In certain configurations, the method may be a swingadsorption method and the cycle duration may be for a period greaterthan 1 second and less than 600 seconds or a period greater than 1second and less than 300 seconds; wherein the performing one or moreregeneration steps comprises performing one or more purge steps, whereineach of the one or more purge steps comprise passing a purge streamthrough the self-supporting structure to conduct away at least a portionof the one or more contaminants in the contaminant output stream;wherein the gaseous feed stream may be a hydrocarbon containing streamhaving greater than one volume percent hydrocarbons based on the totalvolume of the gaseous feed stream; wherein a feed pressure of thegaseous feed stream may be in the range between 400 pounds per squareinch absolute (psia) and 1,400 psia; wherein performing the one or moreadsorption steps may be configured to lower the carbon dioxide (CO₂)level to less than 50 parts per million volume; wherein performing theone or more adsorption steps may be configured to lower the water (H₂O)level to less than 105 parts per million volume; wherein the one or moredefined channels comprise two or more channels that are substantiallyparallel and/or the self-supporting structure has a low thermal mass.

As yet another example, a method of manufacturing a processing unit mayinclude: creating a template for a self-supporting structure; disposinga mixture within the template, wherein the mixture has greater than 50%by weight of the active material in the self-supporting structure andthe remaining mixture includes binder material; curing the template andthe mixture to form a self-supporting structure that is maintains asolid form; removing the template from the self-supporting structure,wherein the self-supporting structure is an open-celled structureconfigured to provide one or more defined channels for fluid flow pathsthrough the self-supporting structure based on the template; anddisposing the self-supporting structure within housing of a processingunit having an interior region. In certain configurations, the methodmay include creating a three-dimensional model of the self-supportingstructure having predetermined geometries for one or more definedchannels through the self-supporting structure (e.g., the open-celledstructure is configured to provide defined channels for fluid flow pathsthrough the structure); may include creating a model of a template basedon the three-dimensional model of the self-supporting structure; mayinclude printing a three-dimensional template based on the model of thetemplate; wherein removing the template from the self-supportingstructure may further comprise heating the self-supporting structure andthe template to melt or decompose the template and conduct away themelted template; may include vibrating the template and the mixtureprior to curing the template and mixture to lessen any voids that may beformed between the template and mixture; wherein curing the template andthe mixture may further comprise sintering the binder material andactive material into a cohesive solid structure that is theself-supporting structure; and/or may include creating a plurality ofvalve ports into the housing; and securing a valve to the housing ineach of the plurality of valve ports to form a plurality of valves,wherein each of the plurality of valves is configured to control fluidflow between the self-supporting structure and a location external tothe housing.

Further still, in yet another configuration, a method of manufacturing aprocessing unit is described. The method comprises: extruding a mixtureinto a monolith form comprising a plurality of substantially parallelchannels, separated by thin walls, wherein the mixture has greater than50% by weight of the active material in the self-supporting structureand the remaining mixture includes binder material; drying the monolithform; and calcining the monolith form from 400° C. to 800° C. to form amechanically stable, active monolith form; wherein the plurality ofsubstantially parallel channels have a cross sectional shape that may bea square, a circle, a triangular, or a hexagonal; wherein the celldensity of the monolith form is in a range between 200 cells per squareinch and 2,000 cells per square inch (e.g., cross sectional shape isalong a plane that is perpendicular to the primary flow path for thefeed stream through the self-supporting structure); and wherein thewalls separating the plurality of substantially parallel channels have athickness in the range between 40 micron to 1 millimeter. Further, themethod may include disposing the self-supporting structure withinhousing of a processing unit having an interior region and/or mayinclude creating a plurality of valve ports into the housing; andsecuring a valve to the housing in each of the plurality of valve portsto form a plurality of valves, wherein each of the plurality of valvesis configured to control fluid flow between the self-supportingstructure and a location external to the housing.

Beneficially, the present techniques provide self-supporting structuresthat may be utilized to provide various enhancements over conventionalapproaches. For example, the present techniques may provide structuresthat provide geometric design flexibility and provide custom structuresand flow paths. The custom structures may be an open-celled structureconfigured to provide defined channels for fluid flow paths through thestructure, which enhance the interaction of the active material with thefluid passing through the channels. Further, by utilizing the activematerial to form the self-supporting structure, the working capacity maybe increased and volumetric efficiency may be enhanced, which mayfurther lessen the size of the structure and associated weight of thestructure. The lessening of the size and weight may also lessen theassociated size of the equipment utilized with the housing that containsthe self-supporting structure. The present techniques may be furtherunderstood with reference to the FIGS. 1 to 14 below.

FIG. 1 is a flow diagram 100 of a method for fabricating and using aself-supporting structure in accordance with an embodiment of thepresent techniques. In this diagram 100, the method includes fabricatinga self-supporting structure including active material along with usingthe self-supporting structure. In particular, the method may includedetermining a configuration for the self-supporting structure, as shownin block 102, creating a mold or template for the self-supportingstructure, as shown in block 104, producing the self-supportingstructure as shown in blocks 106 and 108, and forming a processing unitwith the self-supporting structure and utilizing the self-supportingstructure in processing of feeds, as shown in blocks 110 and 112.

The method begins at block 102. In block 102, a configuration for aself-supporting structure is determined. This determination may involvemodeling and identifying various aspects of the self-supportingstructure to enhance process engineering selections, such as determiningthe mechanical features of the self-supporting structure, determiningflow paths (e.g., the level of tortuousness of the flow path) throughthe self-supporting structure, determining the cell size within theself-supporting structure, determining the pressure drop for flowthrough the self-supporting structure, determining the operatingconditions that the self-supporting structure may be subject to duringprocess operations (e.g., pressures, temperatures and streamcompositions) and/or determining the contaminants to be adsorbed by theactive material in the self-supporting structure.

Once the configuration for the self-supporting structure is determined,a mold is created for the self-supporting structure, as shown in block104. The creation of the self-supporting structure may involve modelingthe desired structure and then three-dimensional (3D) printing the moldor template from a specific material. The template material utilized inthe three-dimensional printing may include materials that may bedissolved as part of the self-supporting structure fabrication process,or may be materials that may be removed from the resultingself-supporting structure. For example, the template may includeplastics, such as Acrylonitrile Butadiene Styrene (ABS), polylactide(PLA), and/or other suitable plastics and/or waxes.

Once the mold is created, the self-supporting structure is produced, asshown in blocks 106 and 108. At block 106, the self-supporting structureis created. The creation of the self-supporting structure may involvemixing an active material with organic and/or inorganic binders toprovide a specific formulation. The mixture, which may be an aqueousslurry, may be provided to the mold directly, or may be combined withthe mold inside a container or vessel. The container or vessel may beused to vibrate the mold and mixture to lessen any voids that may beformed between the mold and mixture. Then, the mold and mixture may beprocessed to cure the mixture into a solid form. The processing mayinclude heating the mold and mixture to dry and/or cure the mixture andmelt or decompose the mold. At block 108, the created self-supportingstructure may be verified. The verification of the createdself-supporting structure may include using sensors to obtainmeasurements on the created self-supporting structure to identify voids,fractures and/or non-homogeneous sections of the created self-supportingstructure. The verification may include performing a high temperaturex-ray diffraction on the self-supporting structure. For example, a hightemperature x-ray diffraction scan indicates that an active component of5A zeolite is stable at 860° C. for several minutes and then losesstability, as shown by decreasing peak heights. This analysis may beused to determine maximum temperatures and time for calcination of theself-supporting structures. The mechanical strength of theself-supporting structures is related to calcination temperaturesgreater than 500° C.

Once the self-supporting structure is produced, the self-supportingstructure is formed into a processing unit, as shown in block 110. Theforming the processing unit, may involve disposing the self-supportingstructure within a housing, coupling a head to the housing, coupling oneor more valves (e.g., poppet valves) to the housing and coupling one ormore conduits to the housing and/or one or more of the valves. Theprocessing unit may be an adsorbent bed unit that includes a housing,which may include a head portion coupled to one or more body portions,that forms a substantially gas impermeable partition. The housing mayinclude the self-supporting structure (e.g., formed as an adsorbent bed)disposed within an interior region enclosed by the housing. Variousvalves may be configured to provide fluid flow passages through openingsin the housing between the interior region of the housing and locationsexternal to the housing. Then, the self-supporting structure may beutilized in processing of fluids, as shown in block 112. For example,the processing of feeds may include performing swing adsorption method(e.g., rapid cycle processes) for the removal of one of morecontaminants from a feed stream. Other examples may include utilizingthe self-supporting structure in a catalytic process.

One method for forming the self-supporting structure may involve the useof 3D molds or templates. By way of example, the self-supportingstructure, which may include complex geometries, may be prepared bymodeling techniques (e.g., modeling software) to model the shape of thethree dimensional objects that are used as templates. The modelingsoftware may produce sets of location coordinates (e.g., x, y, zcoordinates), which may be used by a 3D printer to construct a plasticmold or template, in a layer-by-layer method. A high solids aqueousslurry of active material, organic and inorganic binders and otheradditives may be processed and added to the mold. The organic binderacts as a temporary binder to facilitate particle cohesion during lowtemperature processing and drying. The slurry is dried and calcined inthe template (e.g., the plastic 3D printed mold). During the calcinationprocess, which may be performed at 500° C. or higher, the plastic moldmelts or decomposes, the inorganic binder and active material particlessinter into a cohesive, self-supporting structure with a geometric formderived from the mold. As a result, the self-supporting structure may bean open-celled structure configured to provide defined channels forfluid flow paths through the structure, which are based on the template.Various different templates or molds are shown in FIGS. 2A to 7B, asexamples of the different self-supporting structure that may be created.

FIGS. 2A, 2B and 2C are various diagrams 200, 220 and 240 of a mold,combined mold and mixture and resulting self-supporting structure inaccordance with an embodiment of the present techniques. In FIG. 2A, aplastic mold 202 is shown, which may be a 3D printed sacrificialtemplate or mold having a circular prism shape. In FIG. 2B, the mold 202is combined with the mixture 222, which includes active material andbinder. The resulting self-supporting structure 242 is shown in FIG. 2C.The resulting self-supporting structure 242 is a laminar sheet structureof 3A/Si0₂ (e.g., about a 70:30 ratio of active material by weight tobinder by weight for the self-supporting structure (w/w)) formed byintrusion. The self-supporting structure 242 has a 1 inch diameter by 2inch length, total weight of 19.02 grams, which includes 13.3 grams of3A zeolite and 5.7 grams of Si0₂ binder.

FIGS. 3A, 3B and 3C are various diagrams 300, 320 and 340 of a mold,combined mold and mixture and resulting self-supporting structure inaccordance with another embodiment of the present techniques. In FIG.3A, a plastic mold 302 is shown, which may be a 3D printed sacrificialmold having a rectangular prism shape. In FIG. 3B, the mold 302 iscombined with the mixture 322 of binder and active material. Theresulting self-supporting structure 342 is shown in FIG. 3C. Theresulting self-supporting structure 342 is a fractal-type structure of3A/Si0₂ (e.g., about 70:30 w/w) formed by intrusion. The self-supportingstructure 342 has a 2.25 inch width by 2 inch length.

FIGS. 4A, 4B and 4C are various diagrams 400, 420 and 440 of a mold,combined mold and mixture and resulting self-supporting structure inaccordance with yet another embodiment of the present techniques. InFIG. 4A, a plastic mold 402 is shown, which may be a 3D printedsacrificial mold having a rectangular prism shape. In FIG. 4B, the mold402 is combined with the mixture 422 of binder and active material. Theresulting self-supporting structure 442 is shown in FIG. 4C. Theresulting self-supporting structure 442 is a cross-flow structure of3A/Si0₂ (e.g., about 70:30 w/w) formed by intrusion. The self-supportingstructure 442 has a 2.25 inch width by 2 inch length, which has sixfaces of interconnecting channels.

FIGS. 5A and 5B are various diagrams 500 and 520 of a combined mold andmixture and resulting self-supporting structure in accordance with stillyet another embodiment of the present techniques. In FIG. 5A, a plasticmold 502 is shown with a mixture 504 of active material and binder. Themold 502 may be a 3D printed sacrificial mold having a circular prismshape. The resulting self-supporting structure 522 is shown in FIG. 5B.The resulting self-supporting structure 522 is a crescent structure of3A/Si0₂ (e.g., 70:30 w/w) formed by intrusion. The self-supportingstructure 522 has a 2.25 inch diameter by 2 inch length, which may beformed by a calcination process.

FIGS. 6A and 6B are various diagrams 600 and 620 of a mold and aself-supporting structure in accordance with another embodiment of thepresent techniques. In FIG. 6A, a plastic mold 602 is shown, which maybe a 3D printed sacrificial mold having a hexagonal prism shape. Theresulting self-supporting structure 622 is shown in FIG. 6B. Theresulting self-supporting structure 622 is a hexagonal structure of ZSM58/Si0₂ (e.g., 70:30 w/w) formed by intrusion. The self-supportingstructure 622 has a 2.25 inch width by 2 inch length, which may beformed by a calcination method heating the mixture to about 500° C.

FIGS. 7A and 7B are various diagrams 700 and 720 of two monolithstructures in accordance with an embodiment of the present techniques.In FIG. 7A, the self-supporting structure 702 is a circular structure of5A/Si0₂ (e.g., 70:30 w/w) formed by an extrusion process. Theself-supporting structure 622 has a 1 inch diameter by 3 inch length,and has cells that are triangular shaped. In FIG. 7B, theself-supporting structure 722 is a circular structure of 5A/Si0₂ (e.g.,70:30 w/w) formed by an extrusion process. The self-supporting structure722 has a 1 inch diameter by 3 inch depth and has cells that are squareshaped.

To cure the mixture into the self-supporting structure, the thermalstability of active material by high temperature may be assessed. Asnoted above, one of the final steps in creating a self-supportingstructure may include calcination. Calcination at high temperatures,which may include temperatures equal to or greater than 500° C.,dehydrates the zeolite and SiO₂ particle mixture and coalesces themixture into more dense structures that result in enhanced mechanicalstrength. To assess the high temperature stability of the activematerial (e.g., adsorbent or catalyst material) for calcinationpurposes, a high temperature x-ray diffraction may be performed on theself-supporting structure. For example, a high temperature x-raydiffraction scans may provide a representation to indicate that the 5Azeolite (e.g., active material) was stable at a specific temperature fora certain period of time (e.g., about 860° C. for several minutes) andthen loses stability, which may be shown by decreasing peak heights.Accordingly, this type of analysis may be used to determine the maximumtemperatures and time for calcination of the structures. The mechanicalstrength of the self-supporting structures is related to calcinationtemperatures greater than 500° C.

FIG. 8 is an exemplary diagram 800 of an x-ray diffraction scan of theself-supporting structure. In the diagram 800, the x-ray diffractionscan of the self-supporting structure is performed at 860° C. thatmonitored the first 2-theta peaks of 5A zeolite on the two-theta axis802 in degrees versus the number of scans axis 804. The scans may beperformed using an x-ray diffractometer with a high temperatureenvironmental cell. The scans may be performed every minute, whichincludes the 48 second scan time and 12 second reset time. The scans maybe conducted in the 2° to 12° 2 theta region at 860° C. for six hours.

By way of example, the preparation scheme for producing self-supportingstructures resulting from processing the materials in 3D printed plasticmolds or templates. A high solids aqueous mixture of adsorbent zeoliteor catalyst powder and organic and inorganic binder materials wasprepared. The well-mixed slurry was added into 3D printed plastic mold,while vibrating the mold and slurry. The mixture was dried and calcinedto 500° C. or higher inside the plastic mold producing an active,mechanically stable structure with a geometry derived from the mold. Thechannels are defined channels for fluid flow paths through the structurebased on the plastic mold.

For example, 118.3 grams of 3A zeolite powder may be added to acontainer (e.g., a plastic bowl or cup). Then, 126.75 grams of colloidalsilica (40 wt. % solution with 25 nanometers (nm) suspended SiO₂particles) may be added to the 3A zeolite powder in the container. Themixture rapidly heats to 65° C. (e.g., self-heated), due to heat ofadsorption of the water into the 3A zeolite. Then, the sample may becooled to room or ambient temperatures, which results in the mixturebeing a damp solid. Then, it is mixed well for 1 to 2 minutes at 2,000revolutions per minute (rpm). In a separate container, 15.02 grams ofwater and 10.3 grams of 1.5% methylcellulose polymer (used as organicbinder) may be mixed and once mixed, added to the container containingthe 3A zeolite along with the colloidal silica. The combined mixture wasmixed at 2,000 rpm for 2 minutes. The resulting viscous, pourable slurrymay be decanted into a 3D printed plastic mold.

Self-supporting structure may be fabricated from a 3D template intrusionstructures. The intruded adsorbent zeolite structures, aftercalcination, consist of 70:30 weight/weight of zeolite adsorbent to SiO₂binder. The zeolite particles may be in the range between 2 microndiameter and 25 micron diameter. The SiO₂ binder particles used wereeither 25 nanometer (nm) or 100 nm monodisperse particles. The particlesize distribution of the Linde Type A (LTA) adsorbent powders indicatesthat the particle size ranges are 2 micrometer (μm) to 5 μm, with a meanvalue of 4 μm (e.g., Zeolite A (Linde Division, Union Carbide)). Theparticle size distribution of the ZSM-58 adsorbent powders indicatesthat the particle size ranges are 20 μm to 30 μm, with a mean value of25 μm. Zeolite or other inorganic catalytic particles are not inherentlycohesive after a high temperature calcination processes. The organicbinder materials used were a 1% aqueous solution of methyl cellulosederivatives.

Also, the aqueous slurry sample was prepared at 65 weight percentage(wt. %) solids in aqueous slurry. The ratio of adsorbent zeolite to SiO₂(e.g., 25 nm) binder was about a 70:30 (w/w). On a dry basis, the 3Azeolite and SiO₂ are solids, which has formulation targets of a 70:30dry weight ratio. The organic binder (e.g., methyl cellulose and/ormethyl cellulose derivatives) target was 0.06 wt. % organic binder solidin total slurry weight, or 6 wt. % as a 1 wt. % organic binder solutionin total slurry weight.

The aqueous slurry was well mixed using an asymmetric mixer for one tothree minutes at 1,000 to 2,500 revolutions per minute (rpm). Further,small alumina agates were added to reduce any solid agglomerates, ifneeded.

The resulting viscous, pourable slurry was decanted into a 3D printedplastic mold. The structure was vibrated for fifteen to twenty minutesduring addition and afterwards, using a vibrating table.

The LTA zeolite self-supporting structures involved a modified slurrypreparation method because of the rapid temperature increase, as aresult of high H₂0 adsorption. The slurry temperatures increase quicklyfrom room temperature to 70° C. within seconds. The 70° C. temperaturecan decompose common aqueous organic binders, such as methyl cellulose,which cause them to become irreversibly insoluble. Thus, with LTA slurrypreparations, the aqueous organic binder was added to a slurry of LTAand colloidal SiO₂ after the LTA zeolite/SiO₂ mixture had cooled to roomtemperature to avoid damaging the aqueous organic binder properties.

As an example, the self-supporting structure may include an example of3A/SiO₂ (25 nm) slurry and fractal-type structure preparation. Informing the mixture, 118.33 grams of 3A zeolite, a white fine powder,was added to a tared plastic jar. Then, 126.75 grams of colloidal silicawas added to the 3A in the jar and contents were mixed with a spatula.The colloidal silica is 40 wt. % SiO₂ solution, while the diameter sizeof the SiO₂ particles in the solution are 25 nanometers (nm). There wasa rapid temperature rise to 65° C. as the 3A material adsorbed much ofthe water in the colloidal solution. After the sample cooled to roomtemperature, the jar was capped and the contents were placed inside anasymmetric mixer for one to two minutes at 1,500 to 2,000 rpms to mixthe sample, resulting in a gritty, damp solid. In a separate jar, 15.02grams of water were added, followed by 10.32 grams of a 1.5 wt. %methylcellulose organic binder solution. The sample was mixed and theresulting viscous solution was added to the 3A/SiO₂ mixture. Thecombined mixture was mixed using the mixer at 2,000 rpm for two minutes,resulting in a moldable, cohesive sand-like solid. Then, 10.3 grams ofadditional water was added to the solid mixture, along with 8 aluminaagates to eliminate any agglomerated solids. The sample was mixed usingthe mixer at 2,000 rpm for two minutes resulting in a viscous, pourablewhite slurry. In other embodiments, the organic binder solution mayinclude methyl cellulose and/or methyl cellulose derivatives.

The resulting slurry was added to a fractal-type 3D printed plasticmold, such as the mold 302 in FIG. 3A, while vibrating the structure ona vibration table for fifteen minutes to degas and densify (e.g.,vibration procedure that serves to compact the slurry material, andbring solid particles closer together). The vibration of the slurry isperformed to remove trapped air bubbles in the mixture by bringing theair bubbles to the top of slurry. The sample was air dry overnight inthe mold in an oven at 80° C. The sample and mold were then dried at120° C. for ten hours. For example, samples may be gently dried at atemperature, such as 80° C., which is lower than the boiling pointtemperature of water (e.g., 120° C.) for twelve to sixteen hours. Thismethod is performed in a manner to remove the water slowly. Once dried,the sample and mold were removed from the oven and the plastic wallswere removed from the mold. The exposed walls of 3A/SiO₂ were smooth andcrack-free. The plastic mold base remained attached to 3A/SiO₂structure. The structure was then calcined to 500° C. using aprogrammable furnace. The sample was exposed to temperatures around 120°C. for six hours, exposed to temperatures increasing from 120° C. to350° C. for in ten hours, thermally soaked at 350° C. for four hours todecompose the plastic mold, exposed to temperatures increasing from 350°C. to 500° C. for six hours, thermally soaked at 500° C. for six hours,and then cooled to 120° C. Following calcination process, the resultingself-supporting structure has a weight of 121.283 grams of 70:30 w/w3A/SiO₂. The self-supporting structure had a fractal-type geometric form(e.g., FIG. 3C), with dimensions of 2.25 inch width by 2 in length. Thesurfaces of the structure were in very good condition, with only someminor hair-line cracks in the top of the structure.

Various SEM images of a self-supporting structure is shown in FIG. 9.FIG. 9 is exemplary SEM diagrams 900 and 920 of the self-supportingstructure. In these diagrams 900 and 920, the self-supporting structureis calcined ZSM 58/SiO₂ 100 nm (70:30 w/w), which shows high temperaturebinding. In diagram 900, the edge of a zeolite particle is shown by thelight line indicated by arrow 902, while the SiO₂ particles are shown by904. Further, as indicated by region 906, which is expanded into thediagram 920, various 100 nm SiO₂ spheres.

SEM diagrams 900 and 920 in FIG. 9 show that smaller 100 nm SiO₂ spheresact as an inorganic particle glue to bind the 20 micron diameter zeoliteparticles together into a cohesive composite of zeolite and SiO₂particles after 500° C. calcination. The SiO₂ binder particles are toolarge to enter the zeolite pores, but small enough to form adense-packed surface layer on the much larger (e.g., 15 μm to 20 μm)zeolite crystals. High temperature calcination (500° C. to 800° C.)sinters the zeolite and inorganic particles together to form a connectedsolid network that is still porous. The 30 nm to 50 nm diameter space(pores) between the spherical binder particles is large enough forreactant gases to access the zeolite particles where catalytic and/orseparation processes can occur.

Colloidal silicas, when used as binders for adsorbent or catalystpowders, are a very weak bonding agent at low temperatures. However, thebonding strength of the Colloidal silicas increase dramatically with500° C. to 800° C. calcination temperatures, if there are enough silicaparticles to make point-to-point contact and also bridge theinterstitial spaces between the larger adsorbent particles, as shown inFIG. 9. During drying, prior to the 500° C. to 800° C. calcinationprocess, the slurry shrinks during water loss and the adsorbentparticles are pulled closer together, surrounded by a thin layer of SiO₂particles.

As another example, SEM images of a self-supporting structure is shownin FIGS. 10A and 10B. FIGS. 10A and 10B are exemplary SEM diagrams 1000and 1020 of a self-supporting structure. In these diagrams 1000 and1020, the self-supporting structures are monoliths, such as monolith1002 in diagram 1000 and monolith 1022 in diagram 1020. These monoliths1002 and 1022 are 5A/SiO₂ 25 nm (70:30 w/w) extruded monoliths (e.g.,include 70 wt. % active 5A zeolite and 30 wt. % SiO₂ binder, which are25 nm diameter SiO₂ particles). The diagram 1000 in FIG. 10A has thesquare cell structure from FIG. 7B, while the diagram 1020 in FIG. 10Bhas the triangular cell structure from FIG. 7A. The two monoliths, asquare-celled monolith 1002 and a triangular-celled monolith 1022, wereextruded using the same formulation that was used to produce theintrusion structures above that utilized 3D printed molds. The monolithswere calcined to 750° C. The square-celled monolith 1002 has cell wallthickness 1004 of about 280 μm, and the square-shaped channels areapproximately 700 μm by 700 μm. Specifically, the square-shaped channelshave a cell length 1006 of 700 μm and cell width 1008 of 700 μm. Theresulting structure yields a cell density of approximately 650 cells persquare inch (cpsi). The triangular-celled monolith 1022 has cell wallthickness 1024 of about 200 μm, a side length 1026 of about 1.274 μm anda height 1028 of about 1,060 μm.

In this example, the same formulation utilized to produce aself-supporting structure having custom and complex geometries for theflow passages or channels, as shown in monoliths 1002 and 1022, was alsoapplied to a ceramic extrusion method to produce active materialmonoliths instead of inactive ceramic monoliths. The resulting structuremay be an open-celled structure configured to provide predefinedchannels for fluid flow paths through the respective monoliths 1002 and1022.

Extruded ceramic monoliths involve very high “firing” temperatures(e.g., 1,200° C. to 1,500° C.) to achieve mechanical strength. Afterfiring, these ceramic monoliths are typically used as inert supportstructure (e.g., inorganic support material or inactive support materialwith the streams passing through the monolith or the environmentalconditions the monolith is exposed to during operations). Thesemonoliths, after firing, are usually post-coated with a thin layer ofactive material. So, the purpose of the ceramic monolith is to act as asubstrate/support that provides mechanical strength for the activecoating. The ceramic monolith structure, because of its open channelgeometry, provides laminar flow and low pressure drop.

The extruded active material monoliths formed by the present techniquesare made to be formed from 70% by weight of active material, calcined tomuch lower temperatures than ceramics (e.g., calcined to 500° C. to 650°C.). The lower temperatures are utilized to maintain activity of thezeolite. The strength for the resulting self-supporting structures isprovided by the inorganic SiO₂ and/or clay binders. However, theself-supporting structures, while mechanically stable, are not nearly asstrong as ceramic monoliths. While clay may be used as a binder forzeolites, it does not provide the strength of sintered SiO₂.

FIG. 11 is an exemplary diagram 1100 of powder x-ray diffraction overlaypatterns 1106 and 1108 of samples from inner and outer walls of extruded5A/SiO₂ monoliths that match 5A zeolites. As shown in this diagram 1100,the 5A zeolite structure survived the extrusion and calcination methodand the outer co-extruded wall and inner cells are the same formulation.The patterns 1106 and 1108 of the interior cells and exterior wall ofthe sample indicate that the material in the interior walls and exteriorwalls is the substantially similar, which are shown along a two-thetaaxis 1102 in degrees (deg) against intensity counts axis 1104.

As a selection for the active material, the zeolite type A (e.g., LTAstructures), such as 3A, 4A and/or 5A, are highly porous adsorbents thathave a high affinity and high capacity to adsorb water, as well as othermolecules that have dimensions small enough to fit into the uniformpores of these structures. Accordingly, processes that involve dryingand purification of gases and liquids rely on the adsorption capacityand efficiency of LTA-type zeolites, such as swing adsorption methods.These 3A, 4A, 5A LTA-type zeolites have the ability to readily adsorbwater over a wide range of conditions. They also release the adsorbedwater when heated, without the zeolite structure degrading. Thus, theyhave the ability to cycle between releasing water when heated andreadsorbing water upon cooling.

The use of 3A in water desorption is shown in relation to athermogravimetric analysis (TGA). The TGA was performed by starting witha 3A zeolite powder without binder additives. The TGA experiment yieldsdata on weight loss to the sample versus temperature, as shown in FIG.12.

FIG. 12 is a diagram 1200 of the weight loss for 3A, due to loss ofadsorbed water, as a function of temperature. In this diagram 1200, afirst response 1208 and a second response 1210 are shown along a timeaxis 1202 in minutes (min), a weight percentage axis 1204 in percent anda temperature axis 1206 in ° C. The sample was heated in air from 30° C.to 600° C., at a rate of 10° C. per minute, as shown along the secondresponse 1210. The first response 1208 represents a total weight loss of15.3%, indicating that the 3A powder had adsorbed 15.3% by weight ofwater at ambient conditions. The adsorbed water was removed from thesample at 280° C. (e.g., 25 minutes times 10° C./minute plus 30° C.starting temperature).

Further enhancements may be described by comparing H₂O desorption in 3Apowder with H₂O adsorption in a 500° C. calcined 3A/SiO₂ intrusionstructure. As noted below, Table 1 compares the water adsorption in acalcined 3A/SiO₂ (e.g., 70:30 w/w) structure, to the water desorptionresults in response 1208 of FIG. 12 on the 3A powder.

TABLE 1 3A in 3A powder Agreement Wt structure 3A wt. % TGA resultbetween 3A/Si0₂ increase (dry, increase (above) wt. TGA wt. lossstructure 3A wt. Structure due to Wt. % 500° C.) + due to loss due toand structure wt. after (%) in 3A wt. Si02 wt wt. after H₂0 increase inH₂O H₂0 H₂0 H₂O uptake 500° C. 3A/SiO₂ calcd. calcd 3 days RT uptake3A/SiO₂ uptake uptake desorption (% of (grams) structure (grams) (grams)(grams) (grams) structure (grams) (%) (%) agreement) 20.560 70% 14.3926.168 22.837 2.217 11.07% 16.609 15.4% 15.3% 993%

In Table 1, the 3A/SiO₂ structure used in the comparison is similar tothat in FIG. 2C, which is a 70:30 w/w 3A:SiO₂ laminar sheet monolithobtained by the method described above. The structure was calcined to500° C. to decompose the 3D printed plastic mold and organic binder andsinter the 3A and Si_(O2) 25 nm particles together. The 3A/Si0₂ laminarsheet structure was stored in a 120° C. furnace, after 500° C.calcination process. The 3A component of the structure was expected tohave no adsorbed water. The 3A/SiO₂ structure, which is 1 inch d by 2inch length, was weighed at 120° C. from the furnace and its weight, asrecorded in Table 1 was 20.560 grams, which has 70% of the 20.560 gramtotal weight, or 14.392 grams is the 3A component. The remaining 30% ofthe 20.560 grams of total weight, or 6.168 grams, is the 25 nm diameterSiO₂ binder particles.

After weighing the 3A/SiO₂ structure devoid of water (H₂O), thestructure was exposed on a lab bench for seventy-two hours to ambientconditions. After seventy-two hours of being exposed to ambientconditions, the 3A/SiO₂ structure was re-weighed, and its weight was22.837 grams. This increase in weight was 11.07%, which is a result ofadsorbing 2.217 grams of water from the ambient air. The majority of thewater could only be adsorbed by the 3A component in the 3A/SiO₂structure. When determining the water uptake for the 3A component of thestructure, it corresponds to a 15.4% weight increase. This weightincrease is similar to the 15.3% weight loss in 3A powder, due to waterdesorption in response 1210 of FIG. 12. As a result, the weight increasein the 3A/Si0₂ laminar sheet structure indicates that the 3A componentin the structure is accessible to the water molecules, but this ambientmoisture test does not provide information about the rate of access.

In recent tests, the rate of access to 3A, by adsorbing gas molecules,may be hindered by the 25 nm SiO₂ binder, especially at elevatedcalcination temperatures (700 C+). Accordingly, the method may includeadjustments to the binder to enhance access to the pores.

For examples, the 3A component in the 3A/SiO₂ structure is porous. The“windows” or pores of the 3A structure have openings of 3 angstromssize. Water molecules have a diameter of about 2.8 angstroms and may fitinto the 3A structure or “adsorbed” to the inside of the 3A structure.The SiO₂ binder is non-porous. The SiO₂ spheres do not have pores andthus, do not adsorb water into its structure. The water can wet thesurface of the SiO₂ spheres, but that amount of water may be a verysmall fraction of the total amount of water that could be adsorbed by a3A zeolite (70 wt. %)/SiO₂ (30 wt. %) structure. Thus, the 3A zeolitecomponent is the primary material to adsorb water in the 3A/SiO₂composite structure. TGA (thermal gravimetric analysis) measures weightloss versus temperature. FIG. 12 is the TGA analysis of 3A zeolite only.It shows that the 3A powder lost 15.3% of weight, which is due todesorbing the water that it adsorbed under ambient conditions.

From the example above, this TGA result on 3A zeolite powder isapproximately equal to the 15.4% weight gain in the 3A/SiO₂ structure inthe example due to adsorption of water under ambient conditions. Thenearly identical TGA desorption (weight loss) result and adsorption(weight gain) result in the 3A/SiO₂ structure shows that the 3A zeolitecomponent was accessible to the water.

As an additional enhancement, gas adsorption break-through test werealso performed on the self-supporting structures. A gas adsorptionbreak-through unit, which is referred to as NatGas Unit, was used tomeasure gas adsorption and break-through profiles of coated substrates.A sample of known weight is wrapped to prevent gas bypass and insertedinto a tube in the gas adsorption break-through unit. The samples areexposed to a total 1,000 standard cubic centimeters per minute (sccm)gas flow rate, comprised of 300 sccm N₂ saturated with H₂O at 25° C.,100 sccm He and 600 sccm N₂. The gas break-through is monitored by amass spectrometry. The gas flow measurement term of sccm representscm3/min at standard temperature and pressure.

As part of this testing, an aqueous slurry with 35 wt. % solids,comprised of 3A/SiO₂ (70:30) and methyl cellulose (temporary organicbinder), was formulated, as described above in the example 3A/SiO₂slurry preparation. The slurry was applied to an Al₂O₃ ceramic monolith,which has dimensions suitable for testing in the gas adsorptionbreak-through unit. The washcoat on the ceramic monolith had a similarcomposition to the self-supported structures after calcination. Thus,the 3A/SiO₂ washcoated monolith was used as a suitable surrogate for theself-supporting intrusion and extrusion structures and, hence,breakthrough results should be and are expected to be comparable.

In this testing, the 900 cpsi Al₂O₃ monoliths had dimensions of 0.5 inchd by 1 inch L, 30% wall porosity and 55% open frontal area. Thestarting, uncoated weight of the monolith was 4.099 gram. Two coatingsof the slurry were applied by conventional washcoating techniques andthe sample was dried and calcined to 500° C. The sample weight aftercalcination was 4.893 grams. The resulting 3A/SiO₂ (25 nm d) washcoatedmonolith contained approximately 0.556 gram of 3A adsorbent and was arepresentative sample for formulations used in self-supporting intrusionand extrusion structures. Prior to break-through testing, the 3A/SiO₂coated monolith was dried for twelve hours at 150° C. and 100 sccm Heflow.

FIGS. 13A and 13B are diagrams 1300 and 1320 of break-through profiles.The breakthrough profile is reasonably sharp. In FIG. 13A, the Heresponse 1306 and H₂O response 1308 are shown along a time axis 1302 inminutes versus a mass spectrometer axis 1304 in counts per second towater. The estimated rate of water feed is 5.48 milligrams (mg) perminutes (min). The estimated time for 0.55 grams of 3A in the 3A/SiO₂washcoat to adsorb water before break-through is 25 minutes (e.g., 30minutes at uptake level off minus 5 minutes at beginning of uptake). Theresponse 1306 represents a blank trace (e.g., no sample), which fromtime 0 to 50 minutes of dry He purge and the response 1306 is flat andnear the baseline, indicating no counts for H₂O. Then, after 50 minutes,the valve switches to feed humidified stream, which may be primary anitrogen stream N₂. The response 1306 rises vertically as the massspectrometer shows increasing counts per second of H₂O, until the H₂O isremoved at 300 minutes. Then, the response 1306 returns to the baselineindicating no counts of H₂O. The response 1308 shows a shows a similarexperiment through a sample of 3A/SiO₂ coated onto Al₂O₃ ceramicmonolith. As indicated by this response 1308, it is about 5 minuteslonger for the response 1308 to rise as compared to the response 1306for the blank sample, which indicates that H₂O breakthrough is beingslowed by the adsorption of H₂O in the 3A component until the samplereaches water saturation and equilibrium.

In FIG. 13B, the He response 1326 and H₂O response 1328 are shown alonga time axis 1322 in minutes versus a normalized fractional concentrationof H₂O axis 1324 in C/Co, which expresses the normalized fractionalconcentration of H₂O being measured by a mass spectrometer as a functionof time axis 1322. In this diagram 1320, the 3A adsorbs water for about25 minutes, indicating that the 3A adsorbent particles are accessiblewithout signs of major diffusional hindrance. The response 1326represents a dry He purge passing through an empty cell for 5 minutes,which is flat and near the baseline. Once a valve is switched to feedhumidified He stream, the mass spectrometer indicates a breakthrough ofthe Helium (He) at time 0 minutes. In comparison, the response 1328represents a sample cell with 3A/SiO₂ washcoated ceramic monolithresponding to a humidified He flow. The response 1328 indicates thenormalized H₂O concentration versus time. Accordingly, it indicates thatit takes several minutes (e.g., about 25 minutes) until the 3A componentin the sample is saturated with H₂O and the full concentration (100%) ofH₂O is indicated by the mass spectrometer.

FIGS. 13C and 13D are diagrams 1340 and 1360 of transition feed versuspurge temperature profiles. In this diagrams 1340 and 1360, ceramicmonoliths perform significantly better to thermal transitions than themetal monoliths. The ceramic materials should perform similar to theself-supported active structures, which have a low thermal massstructures similar to ceramics and should exhibit similar thermal swingadvantages. Further, the self-supported structures of the presenttechniques are composed of a majority of active material, which is thematerial that the thermal swing process is attempting heat and coolrapidly.

In the diagrams 1340 and 1360, a cyclic process was used that involvedfluid flows for 20 seconds each for feed and purge steps of the cycle.The gas flow rates were 14 standard cubic feet per minute (scfm) forfeed gas and 22 scfm for purge gas. Nitrogen gas was used for feed andpurge streams, which were introduced at opposite ends of the monolithsor bed. The feed stream was at ambient temperature, while the purgestream was at 180° C. To monitor the temperature, fast responsethermocouples were used to measure and store the temperatures, which hada first thermocouple positioned to measure temperatures at the feed gasinlet side of the structure and a second thermocouple positioned tomeasure temperatures at the purge gas inlet side of feed gas.

In FIG. 13C, the temperature responses 1346 and 1348 are shown along atime axis 1342 in seconds versus a temperature axis 1344 in ° C. Themetal monolith used as a sample bed were three monoliths of 0.75 inchesin diameter by 2 inches in length, made of stainless steel, with celldensity greater than 1,000 cell per square inch (cpsi), with 50 micronthick cell walls and a center steel arbor of ⅜ inch diameter. Themonolith cells were coated with thin layer of adsorbent and themonoliths were wrapped with fibrous insulation to prevent gas bypass.The resulting structure was loaded into a sample tube. The diagram 1340with temperature responses 1346 and 1348 for the metal monolithsindicate a large temperature gap of approximately 70° C. in respondingto temperature transitions between 180° C. purge gas and ambienttemperature feed gas. This indicates that the metal monolith isadsorbing significant heat into the structure.

In FIG. 13D, the temperature responses 1366 and 1368 are shown along atime axis 1362 in seconds versus a temperature axis 1364 in ° C. Theceramic monolith used as a sample bed includes the monoliths of 0.75inch diameter and 2 inch length, made of alumina ceramic, with celldensity of 900 cpsi, with 100 micron thick cell walls, no center arbor.Ceramic monoliths were wrapped with fibrous insulation to prevent gasbypass. The resulting structure was loaded into a sample tube. Thediagram 1360 with the temperature responses 1366 and 1368 for thealumina ceramic monoliths indicate that the temperature transitionsduring the temperature cycle has a smaller temperature change than themetal monolith, as shown in FIG. 13C. The temperature gap in theresponses 1366 and 1368 for the ceramic monoliths is approximately 20°C. during cycling process. This indicates that the ceramic monolithsadsorb less heat into the structure than the metal monoliths, as shownin FIG. 13C.

Testing may be performed on the self-supporting structure. For example,an ambient air exposure test may be performed, which is a passive test.There is no driving force to add water to the 3A/SiO₂ structure. Itslowly adsorbs water from the air and it is affected by conditions ofrelative humidity and temperature, which are measured. This testdelivers a calibrated flow of gas in sccm with known concentration ofwater and monitors the time until the 3A/SiO₂ structure has adsorbedwater to its capacity. There is a mass spectrometer instrumentmonitoring the exit gas stream from the structure. The mass spectrometerinstrument is monitoring water in the gas versus time. When water isdetected, which is referred to as “breakthrough”, it indicates that the3A component of structures is saturated with water at these specificconditions and cannot adsorb more water.

As yet another example, the self-supporting structure may be formedthrough an extrusion process. For example, a mixture may be formed intoa monolith form comprising defined channels (e.g., substantiallyparallel channels), separated by thin walls, wherein the mixture hasgreater than 50% by weight of the active material in the self-supportingstructure and the remaining mixture includes binder material. Then, themonolith form may be dried and the monolith form may be calcined withina temperature range between 400° C. and 800° C. to form a mechanicallystable, active monolith form. The monolith form may include the definedchannels have a cross sectional shape (e.g., cross sectional shape thatis along a plane that is perpendicular to direction of primary flowthrough the respective channel) that may be a square, a circle, atriangular, a hexagonal or any other suitable shape. The cell density ofthe monolith form may be in a range between 200 cells per square inchand 2,000 cells per square inch. The walls separating the channels mayhave a thickness in the range between 40 micron and 1 millimeter.

Once formed, the monolith form, which is the self-supporting structure,may be disposed within a housing of a processing unit having an interiorregion. The housing may have a plurality of valve ports created into thehousing (e.g., drilled or formed into the housing); and valves may besecured to the housing in each of the valve ports to form the valves,wherein each of the valves is configured to control fluid flow betweenthe self-supporting structure and a location external to the housing.

In certain configurations, the present techniques may be utilized in aswing adsorption method (e.g., a rapid cycle process) for the removal ofone of more contaminants from a feed stream. In particular, the presenttechniques involve a one or more adsorbent bed units to perform a swingadsorption method or groups of adsorbent bed unit configured to performa series of swing adsorption methods. Each adsorbent bed unit isconfigured to perform a specific cycle, which may include an adsorptionstep and a regeneration step. By way of example, the steps may includeone or more feed steps, one or more depressurization steps, one or morepurge steps, one or more recycle steps, and one or morere-pressurization steps. The adsorption step may involve passing a feedstream through the adsorbent bed to remove contaminants from the feedstream. The regeneration step may include one or more purge steps, oneor more blowdown steps, one or more heating steps and/or one or morerepressurization steps.

The present techniques may also include active materials that areconfigured to perform at various operating conditions. For example, thefeed pressure may be based on the preferred adsorption feed pressure,which may be in the range from 400 pounds per square inch absolute(psia) to 1,400 psia, or in the range from 600 psia to 1,200 psia. Also,the purge pressure may be based on the sales pipeline pressure, whichmay be in the range from 400 psia to 1,400 psia, in the range from 600psia to 1,200 psia.

In addition, other configurations may involve enhancements foradsorption structures that may be formed primarily from activecomponent. Beneficially, the use of primarily active components mayprovide significantly cheaper, higher working capacity potential insmaller volume, cell uniformity, increased geometric and engineeringflexibility, and/or lower thermal mass. For example, the self-supportingstructures may be formed into self-supporting structure monoliths,self-supporting 3D structures (e.g., indirect from 3D printing), and/orself-supporting structure foams. The self-supporting structure monolithsmay be preferred for applications, such as pressure swing adsorption,which involves low pressure drop.

By way of example, the compositions of the self-supporting structuremonoliths may include thin films that are used with natural gas stream,which indicate that the compositions are beneficial. One configurationincludes extruded self-supporting structure monoliths. Thisconfiguration may lack a preferred breakthrough front because gasdiffusion hindrance issues and/or damaged adsorbent crystals.

FIG. 14 is an exemplary diagram 1400 of self-supporting structuremonolith test results. As shown in FIG. 14, an extruded self-supportingstructure monolith may be formed of a composition of 5A/SiO₂ to 25 nm(70:30) and may be calcinated at 750° C. As shown in the diagram 1400, aplot of a natural gas test is shown. In the diagram 1400, a firstresponse 1408 of Helium and a second response 1406 of Water (H₂0) areshown along a time axis 1402 in minutes (min) and a normalizedfractional concentration of H₂O axis 1404 in normalized concentration(C/Co). The first response 1408 is a breakthrough curve increases at anangle to the right, which may preferably be vertical. Gas permeancetesting may be performed to determine if extrusion pressures (e.g., 2000pounds per square inch gauge (psig) to 4,000 psig) needed to formself-supported extruded monoliths, have diminished the macro poresystem, thus increasing diffusional hindrance. Similarly, a H₂Obreakthrough test may be performed to determine whether the extrusionpressure damaged the adsorbent crystals. This testing may include usingthe same sample and/or the sample holder, which may be performed aftergas permeance test completed. The gas permeance testing, may involveusing a carver press to compress disks of self-supporting structuresmonoliths compositions to 5,000 psig to simulate monolith extrusionpressures.

In one or more configurations, measurements of the effects on gaspermeance are obtained in disk structures of self-supporting structuremonolith compositions. For example, the effects on gas permeance may becompared with extrusion-type pressures, such as disks compressed to5,000 psig before drying and/or calcination or may be compared withvarious polyethylene sphere additives. The gas permeation resultsindicate that a method of using polyethylene spheres as an approach toenhance gas transport in self-supported compositions, appears to beeffective. The effects of macro-pore additive may include greater impactwith smaller (e.g., 25 nm) binder system than in 100 nm binder system.The larger effect on average pore size of 25 nm binder system isenhanced because 25 nm particles (e.g., 25 nm SiO₂ particles) aresmaller than 100 nm particles (e.g., 100 nm SiO₂ particles) and thereare more 25 nm particles for same composition of 5A/SiO₂ w/w ratio than100 nm particles. By way of example, the self-supported structures mayutilize pore engineering methods, which may involve using polyethylenespheres. The adsorbent (e.g., 5A) may be a combination of macro-poreadditives (polyethylene spheres dimensions of 2 to 4 micrometerspherical) and an inorganic binder (e.g., SiO₂ particles colloidalsolution of 40 weight percent (wt. %) of 25 nm SiO₂ or 40 wt. % of 100nm SiO₂.

FIGS. 15A and 15B are exemplary diagrams 1500 and 1520 of polyethylenespheres, which may be used in self-supporting structure monoliths. FIG.15A is a diagram 1500 of spheres, which includes a first diameter 1502and a second diameter 1504. The first diameter 1502 and second diameter1504 may be in the range between 2 micrometers and 4 micrometers. FIG.15B is a diagram 1520 of spherical macro-porous holes after burnoutafter 500° C. calcination in a 5A/SiO₂ sample (with 5% polyethylenespheres).

To assess self-supporting structure monolith compositions, testing maybe performed to determine porosity (e.g., gas permeance and/or mercuryporosimetry testing) and capacity (e.g., H₂O uptake by adsorbent). Byway of example, the testing may include gas permeance testing, wateruptake testing and mercury porosimetry testing. For the gas permeancetesting, the gas permeance is compared with the feed pressure. Theprobing porosity system of self-supporting structure monolith disks mayinvolve deriving information about permeability, connected porosity,pore diameter, and any combination thereof. The gas permeanceconfiguration of the test unit may include a housing having an interiorregion configured to hold a disk, a pressure meter at the inlet side ofthe housing, and a flow meter at the outlet side of the housing. Theformulated disks may be compressed to 5,000 psig, which is used to mimicthe monolith extrusion pressure in the range between 2,000 psig and4,000 psig. The gas permeance testing may include passing variousstreams through the self-supporting structure monolith disks, such asHelium (He) to provide a non-adsorbing trace line and other gases havingmass and viscosity (e.g., four other compositions, which are runseparately through the disks). These different streams may includeHelium (He), Nitrogen (N₂), carbon dioxide (CO₂), methane (CH₄) andArgon (Ar). The gas permeance testing may include measuring the gaspressure on an inlet side of the test unit and measuring the fluid flowon the outlet side of the test unit. The associated measurements provideinsights of the open pore system.

In addition, the testing may include water uptake testing, which may beperformed after the gas permeance testing. This testing may involvedetermining H₂O breakthrough. The water uptake testing configuration ofthe test unit may include a housing having an interior region configuredto hold a disk and a humidity sensor at the outlet side of the housing.The water uptake testing may involve probing working capacity of zeoliteadsorbent in self-supporting structure monoliths, disks or films. Thetesting may include 40% relative humidity (RH) water on gas feed side tobe used for measuring breakthrough humidity versus time on outlet side.The weight of disk with adsorbent composition is known and is used tocalculate and compare breakthrough time. This indicates the amount ofthe adsorbent (e.g., zeolite) is accessible (e.g., working capacity) ascompared to the known amount of adsorbent.

Further still, the testing may include Mercury (Hg) porosimetry testing,which may be performed after the gas permeance testing and water uptaketesting. The Hg porosimetry testing may include determining the Hgintrusion. The Hg porosimetry testing configuration of the test unit mayinclude a housing having an interior region configured to hold a disk.The testing may include probing porosity system of the disks using Hgliquid and pressures (e.g., ambient to 60,000 psig). This testing may beused to determine pore diameter and/or pore volume. Portions or piecesof formulated disks may be used in permeance and breakthrough tests aresent to Micromeritics Analytical Services Company for testing.

Various observations are shown in FIGS. 16A to 16D. In particular, FIGS.16A, 16B, 16C and 16D are exemplary diagrams 1600, 1620, 1640 and 1660of a permeance measurements in accordance with embodiments of thepresent techniques. In these diagrams 1600, 1620, 1640 and 1660, the gaspermeances of extrusion-type samples tested are high (e.g., 10^(e-6) to10^(e-5) moles/s m2 Pa). The self-supporting structure monolith diskshave a composition that is an adsorbent zeolite to SiO₂ (e.g., 25 nm)binder having about a 80:20 (w/w) ratio. The disks are compressed at5,000 psig.

FIG. 16A is an exemplary diagram 1600 of permeance measurements forHelium (He) gas passing through the self-supporting structure monolithdisks. In this diagram 1600, various response points, such as points1606, 1607, 1608 and 1609, are shown along a permeance axis 1604 inmoles per second meter squared Pascal (moles/s m² Pa) against a pressureaxis 1602 in kilo-Pascal (kPa). In particular, the points, such aspoints 1606, shown by x's represent the disk made of 5A/SiO₂ 100 nmhaving 10% w/w macropore additive before calcination, while the points,such as points 1607, shown by the squares represent the disk made of5A/SiO₂ 25 nm having 5% w/w macropore additive before calcination, andthe points, such as points 1608, shown by the triangles represent thedisk made of 5A/SiO₂ 100 nm having 0% w/w macropore additive beforecalcination, and the points, such as points 1609, shown by the diamondsrepresent the disk made of 5A/SiO₂ 25 nm having 0% w/w macroporeadditive before calcination.

FIG. 16B is an exemplary diagram 1620 of permeance measurements forNitrogen (N₂) gas passing through the self-supporting structure monolithdisks. In this diagram 1620, various response points, such as points1626, 1627, 1628 and 1629, are shown along a permeance axis 1624 inmoles per second meter squared Pascal (sm2 Pa) against a pressure axis1622 in kilo-Pascal (kPa). In particular, the points, such as points1626, shown by x's represent the disk made of 5A/SiO₂ 100 nm having 10%w/w macropore additive before calcination, while the points, such aspoints 1627, shown by the squares represent the disk made of 5A/SiO₂ 25nm having 5% w/w macropore additive before calcination, and the points,such as points 1628, shown by the triangles represent the disk made of5A/SiO₂ 100 nm having 0% w/w macropore additive before calcination, andthe points, such as points 1629, shown by the diamonds represent thedisk made of 5A/SiO₂ 25 nm having 0% w/w macropore additive beforecalcination.

FIG. 16C is an exemplary diagram 1640 of permeance measurements formethane (CH₄) gas passing through the self-supporting structure monolithdisks. In this diagram 1640, various response points, such as points1646, 1647, 1648 and 1649, are shown along a permeance axis 1644 inmoles per second meter squared Pascal (sm2 Pa) against a pressure axis1642 in kilo-Pascal (kPa). In particular, the points, such as points1646, shown by x's represent the disk made of 5A/SiO₂ 100 nm having 10%w/w macropore additive before calcination, while the points, such aspoints 1647, shown by the squares represent the disk made of 5A/SiO₂ 25nm having 5% w/w macropore additive before calcination, and the points,such as points 1648, shown by the triangles represent the disk made of5A/SiO2 100 nm having 0% w/w macropore additive before calcination, andthe points, such as points 1649, shown by the diamonds represent thedisk made of 5A/SiO2 25 nm having 0% w/w macropore additive beforecalcination.

FIG. 16D is an exemplary diagram 1660 of permeance measurements forcarbon dioxide (CO₂) gas passing through the self-supporting structuremonolith disks. In this diagram 1660, various response points, such aspoints 1666, 1667, 1668 and 1669, are shown along a permeance axis 1664in moles per second meter squared Pascal (sm2 Pa) against a pressureaxis 1662 in kilo-Pascal (kPa). In particular, the points, such aspoints 1666, shown by x's represent the disk made of 5A/SiO₂ 100 nmhaving 10% w/w macropore additive before calcination, while the points,such as points 1667, shown by the squares represent the disk made of5A/SiO₂ 25 nm having 5% w/w macropore additive before calcination, andthe points, such as points 1668, shown by the triangles represent thedisk made of 5A/SiO₂ 100 nm having 0% w/w macropore additive beforecalcination, and the points, such as points 1669, shown by the diamondsrepresent the disk made of 5A/SiO₂ 25 nm having 0% w/w macroporeadditive before calcination.

As shown by the diagrams 1600, 1620, 1640 and 1660, the permeanceimproves between the addition of 0% polyethylene spheres, 5%polyethylene spheres and 10% polyethylene spheres to the composition.Further, the differences between 25 nm binder and 100 nm binder samplesare shown in these diagrams 1600, 1620, 1640 and 1660. Accordingly, theaddition of 5% polyethylene spheres to disk composition having 25 nmdiameter yield similar permeance to disk compositions for 100 nmdiameter (100 nm) binder with 0% polyethylene spheres.

The average pore diameter may be determined from the gas permeancemeasurements and/or Knudsen and Poiseuille models, as shown in FIG. 17.FIG. 17 is an exemplary diagram 1700 of average pore diameter based ongas permeance measurements in accordance with an embodiment of thepresent techniques. In the diagram 1700, the effect of the macroporeadditive in disks for the 25 nm binder material versus 100 nm bindermaterials. In this diagram 1700, various disks, which have variouscompositions are shown along a pore diameter axis 1704 in micrometers(μm) against a sample identification (ID) axis 1702. The disk may have acomposition of 5A/25 nm SiO₂ particles having 0% polyethylene spheres,as shown by response 1706, while the disk may have a composition of5A/25 nm SiO₂ particles having 5% polyethylene spheres, as shown byresponses 1708. The disk may have a composition of 5A/100 nm SiO₂particles having 0% polyethylene spheres, as shown by response 1710,while the disk may have a composition of 5A/100 nm SiO₂ particles having5% polyethylene spheres, as shown by responses 1712, and the disk mayhave a composition of 5A/100 nm SiO₂ particles having 10% polyethylenespheres, as shown by responses 1714.

As shown by the responses 1706, 1708, 1710, 1712 and 1714, the averagepore diameters may indicate the effects of pore engineering macro-poreadditives. In the model, the calculations indicates the average porediameter sizes between 0.6 micrometers to 2.0 micrometers. The additionof macropore additives have a greater impact on increasing average porediameters of 5A compositions containing smaller diameter bindermaterials (e.g., 25 nm) as compared to the larger diameter bindermaterials (e.g., 100 nm). The larger effect on average pore size of 5Acompositions containing smaller diameter binder materials (e.g., 25 nm)is attributed to differences in binder particle diameter sizes (e.g., 25nm SiO₂ particles are smaller than 100 nm SiO₂ particles) and/or thelarger number of particles for volume (e.g., more 25 nm particles forsame 5A/SiO₂ w/w ratio than 100 nm particles).

The water uptake testing may be used to generate qualitative results ofwater breakthrough on a self-supporting structure monolith disks. FIG.18 is an exemplary diagram 1800 of water breakthrough in accordance withan embodiment of the present techniques. In the diagram 1800, thecomposition of the self-supporting structure monolith disks may include5A/SiO₂ in a ratio of 80:20 (w/w), wherein the SiO₂ are 25 nm and thecomposition include 5% polyethylene spheres. The water uptake testingmay be performed after gas permeance testing. For example, a disk thatwas tested in a gas permeance test unit has approximately 1.943 gramsmass with a composition of approximately 80:20 5A/SiO₂. In the diagram1800, a first response 1808 of Helium and a second response 1810 ofwater (H₂0) are shown along a time axis 1802 in seconds (s), a relativehumidity axis 1804 in percentage (%) and a concentration axis 1806 inparts per million (ppm). In this diagram 1800, the flow rate is about 90sccm, 38% relative humidity (RH), and 0.00088 grams water per minute (gH₂O/min). The estimated breakthrough time for 15% uptake capacity isabout 15,311 seconds. The response 1810 has an initial sharp, verticalbreakthrough portion, which is followed by a portion of the response1810 flattens to a nearly horizontal line. As a result, the water uptakeand breakthrough graph result indicates that the 5A crystals arefunctional after 5,000 psig compression.

Beneficially, the gas permeation results indicate that the method ofusing polyethylene spheres as one approach to pore engineering iseffective. The use of polyethylene spheres to enhance gas transport inself-supported monolith disk compositions is also effective. Inaddition, pore engineering using macro-pore additives appears to providegreater advantage to compositions with smaller (25 nm) binder materialsthan in 100 nm binder materials at a similar w/w of binder material.These effects may include having a larger effect on average pore size of25 nm binder materials because 25 nm SiO₂ particles are smaller than 100nm SiO₂ particles and there are more 25 nm particles for same volume ofmaterial than 100 nm particles. Accordingly, the pore engineering mayimprove gas transport in self-supported structures, which may bespecifically be used with polyethylene spheres, as an example approachto pore engineering.

Further enhancements in the self-supported structures may be used toenhance the fabrication processes and/or resulting structure. Forexample, the present techniques may include optimizing the order ofcomponents that are added, may include additives to enhance porosity anddiffusional performance, and/or may include additives to enhanceformulation processing (e.g., extruded monolith structures). As a firstenhancement, the order of addition may be used to enhance theself-supported monolith. In this method, the pre-condition adsorbent maybe filled to capacity with water. The order of addition may preventfouling of adsorbent, which may include adding a sodium cationstabilizer in colloidal silica solutions. Also, the order of additionmay involve preventing agglomeration and poor distribution of SiO₂binder particles, as a result of adsorbing the H₂O from the bindersolution. As a second enhancement, the addition of macro pore additivesto the composition. The addition of macro pore additives may improvemacro porosity and reduce diffusional hindrance issues and may involveusing polyethylene spheres (e.g., between 2 μm and 4 μm in diameter). Asa third enhancement, the addition of plasticizing additive to thecomposition. The addition of plasticizing additive, such as claymaterials, to the composition may be used to enhance materialworkability for processing by extrusion or intrusion or other methods.Also, the addition of plasticizing additive may improve structure defectissues that may result from drying and calcining.

By way of example, FIG. 19 is a three-dimensional diagram of the swingadsorption system 1900 having six adsorbent bed units andinterconnecting piping. While this configuration is a specific example,the present techniques broadly relate to adsorbent bed units that can bedeployed in a symmetrical orientation, or non-symmetrical orientationand/or combination of a plurality of hardware skids. Further, thisspecific configuration is for exemplary purposes as other configurationsmay include different numbers of adsorbent bed units. In thisconfiguration, the adsorbent bed units may include self-supportingstructures.

In this system, the adsorbent bed units, such as adsorbent bed unit1902, may be configured for a cyclical swing adsorption method forremoving contaminants from feed streams (e.g., fluids, gaseous orliquids). For example, the adsorbent bed unit 1902 may include variousconduits (e.g., conduit 1904) for managing the flow of fluids through,to or from the adsorbent bed within the adsorbent bed unit 1902. Theseconduits from the adsorbent bed units 1902 may be coupled to a manifold(e.g., manifold 1906) to distribute the flow of the stream to, from orbetween components. The adsorbent bed within an adsorbent bed unit mayseparate one or more contaminants from the feed stream to form a productstream. As may be appreciated, the adsorbent bed units may include otherconduits to control other fluid steams as part of the process, such aspurge streams, depressurizations streams, and the like. Further, theadsorbent bed unit may also include one or more equalization vessels,such as equalization vessel 1908, which are dedicated to the adsorbentbed unit and may be dedicated to one or more step in the swingadsorption process.

In certain configurations, the self-supporting structure may be utilizedin an adsorbent bed unit that includes a housing, which may include ahead portion and other body portions, that forms a substantially gasimpermeable partition. The housing may include the self-supportingstructure (e.g., formed as an adsorbent bed) disposed within the housingand a plurality of valves (e.g., poppet valves) providing fluid flowpassages through openings in the housing between the interior region ofthe housing and locations external to the interior region of thehousing. Each of the poppet valves may include a disk element that isseatable within the head or a disk element that is seatable within aseparate valve seat inserted within the head (not shown). Theconfiguration of the poppet valves may be any variety of valve patternsor configuration of types of poppet valves. As an example, the adsorbentbed unit may include one or more poppet valves, each in flowcommunication with a different conduit associated with differentstreams. The poppet valves may provide fluid communication between theadsorbent bed and one of the respective conduits, manifolds or headers.The term “in direct flow communication” or “in direct fluidcommunication” means in direct flow communication without interveningvalves or other closure means for obstructing flow. As may beappreciated, other variations may also be envisioned within the scope ofthe present techniques.

The adsorbent bed comprises adsorbent material formed into theself-supporting structure, which is capable of adsorbing one or morecomponents from the feed stream. Such adsorbent materials are selectedto be durable against the physical and chemical conditions within theadsorbent bed unit and can include metallic, ceramic, or othermaterials, depending on the adsorption process.

In certain configurations, the swing adsorption system, which includesthe active material, may process a feed stream that predominatelycomprises hydrocarbons along with one or more contaminants. For example,the feed stream may be a hydrocarbon containing stream having greaterthan one volume percent hydrocarbons based on the total volume of thefeed stream. Further, the feed stream may include hydrocarbons alongwith H₂O, H₂S, and CO₂. By way of example, the stream may include H₂O asone of the one or more contaminants and the gaseous feed stream maycomprise H₂O in the range of 50 parts per million (ppm) molar to 1,500ppm molar; or in the range of 500 ppm to 1,500 ppm molar. Moreover, thefeed stream may include hydrocarbons and H₂O, wherein the H₂O is one ofthe one or more contaminants and the feed stream comprises H₂O in therange of two ppm molar to saturation levels in the feed stream.

In addition, the present techniques may provide an adsorption systemthat utilizes a rapid cycle swing adsorption method to separate acid gascontaminants from feed streams, such as acid gas from hydrocarbonstreams. Acid gas removal technology may be useful for gas reservesexhibit higher concentrations of acid gas (e.g., sour gas resources).Hydrocarbon feed streams vary widely in amount of acid gas, such as fromseveral parts per million acid gas to 90 volume percent (vol. %) acidgas. Non-limiting examples of acid gas concentrations from exemplary gasreserves include concentrations of at least: (a) 1 vol. % H₂S, 5 vol. %CO₂, (b) 1 vol. % H₂S, 15 vol. % CO₂, (c) 1 vol. % H₂S, 60 vol. % CO₂,(d) 15 vol. % H₂S, 15 vol. % CO₂, and (e) 15 vol. % H₂S, 30 vol. % CO₂.Accordingly, the present techniques may include equipment to removevarious contaminants, such as H₂S and CO₂ to desired levels. Inparticular, the H₂S may be lowered to levels less than 4 ppm, while theCO₂ may be lowered to levels less than 1.8 molar percent (%) or,preferably, less than 50 ppm. As a further example, the acid gas removalsystem may remove CO₂ to LNG specifications (e.g., less than or equal to50 parts per million volume (ppmv) CO₂).

In certain configurations, the active material may be used in a rapidcycle swing adsorption method, such as a rapid cycle PSA process, toremove moisture from the feed stream. The specific level may be relatedto dew point of desired output product (e.g., the water content shouldbe lower than the water content required to obtain a dew point below thelowest temperature of the stream in subsequent process and is related tothe feed pressure). As a first approximation, and not accounting forfugacity corrections as a function of pressure, the water concentrationin ppm that yields a certain dew point varies inversely with thepressure. For example, the output stream from the adsorbent bed may beconfigured to be the cryogenic processing feed stream, which satisfiesthe cryogenic processing specifications (e.g., approximately −150° F.(−101.1° C.) dew point for NGL processes or approximately −60° F.(−51.1° C.) for Controlled Freeze Zone (CFZ) processes. The cryogenicprocessing feed stream specification may include a water content in thestream (e.g., output stream from the adsorbent bed or feed stream to theto be cryogenic processing) to be in the range between 0.0 ppm and 10ppm, in the range between 0.0 ppm and 5.0 ppm, in the range between 0.0ppm and 2.0 ppm, or in the range between 0.0 ppm and 1.0 ppm. Theresulting output stream from the adsorbent beds during the purge stepmay include a water content in the stream to be in the range between 0.0ppm and 7 pounds per standard cubic feet (lb/MSCF).

In one or more embodiments, the present techniques can be used for anytype of swing adsorption method. Non-limiting swing adsorption methodsfor which the present techniques may include pressure swing adsorption(PSA), vacuum pressure swing adsorption (VPSA), temperature swingadsorption (TSA), partial pressure swing adsorption (PPSA), rapid cyclepressure swing adsorption (RCPSA), rapid cycle thermal swing adsorption(RCTSA), rapid cycle partial pressure swing adsorption (RCPPSA), as wellas combinations of these methods, such as pressure and/or temperatureswing adsorption. Exemplary kinetic swing adsorption methods aredescribed in U.S. Patent Application Publication Nos. 2008/0282892,2008/0282887, 2008/0282886, 2008/0282885, 2008/0282884 and 2014/0013955and U.S. Ser. Nos. 15/233,617, 15/233,623, 15/233,631 and 15/233,640,which are each herein incorporated by reference in their entirety.However, rapid cycle may be preferred to process the stream. However,the self-supporting structures may be preferably utilized with rapidcycle swing adsorption methods.

Further, in certain configurations of the system, the present techniquesmay include a specific process flow to remove contaminants, such aswater (H₂O) or acid gas, in the swing adsorption system. For example,the method may include an adsorbent step and a regeneration step, whichform the cycle. The adsorbent step may include passing a feed stream ata feed pressure and feed temperature through an adsorbent bed unithaving an active material structure to separate one or more contaminantsfrom the feed stream to form a product stream. The feed stream may bepassed through the adsorbent bed in a forward direction (e.g., from thefeed end of the adsorbent bed to the product end of the adsorbent bed).Then, the flow of the feed stream may be interrupted for a regenerationstep. The regeneration step may include one or more depressurizationsteps, one or more purge steps and/or one or more re-pressurizationsteps. The depressurization steps may include reducing the pressure ofthe adsorbent bed unit by a predetermined amount for each successivedepressurization step, which may be a single step and/or may be ablowdown step. The depressurization step may be provided in a forwarddirection or may preferably be provided in a countercurrent direction(e.g., from the product end of the adsorbent bed to the feed end of theadsorbent bed). The purge step may include passing a purge stream intothe adsorbent bed unit, which may be a once through purge step and thepurge stream may be provided in countercurrent flow relative to the feedstream. The purge product stream from the purge step may be conductedaway and recycled to another system or in the system. Then, the one ormore re-pressurization steps may be performed, wherein the pressurewithin the adsorbent bed unit is increased with each re-pressurizationstep by a predetermined amount with each successive re-pressurizationstep. Then, the cycle may be repeated for additional feed streams and/orthe cycle may be adjusted to perform a different cycle for a secondconfiguration. The cycle duration may be for a period greater than 1second and less than 600 seconds, for a period greater than 2 second andless than 300 seconds, for a period greater than 2 second and less than200 seconds, or for a period greater than 2 second and less than 90seconds.

Also, the present techniques may be integrated into a variousconfigurations, which may include a variety of compositions for thestreams. Adsorptive separation methods, apparatus, and systems, asdescribed above, are useful for development and production ofhydrocarbons, such as gas and oil processing. Particularly, the providedmethods, apparatus, and systems are useful for the rapid, large scale,efficient separation of a variety of target gases from gas mixtures. Inparticular, the methods, apparatus, and systems may be used to preparefeed products (e.g., natural gas products) by removing contaminants andheavy hydrocarbons (e.g., hydrocarbons having at least two carbonatoms). The provided methods, apparatus, and systems are useful forpreparing gaseous feed streams for use in utilities, includingseparation applications. The separation applications may include dewpoint control; sweetening and/or detoxification; corrosion protectionand/or control; dehydration; heating value; conditioning; and/orpurification. Examples of utilities that utilize one or more separationapplications include generation of fuel gas; seal gas; non-potablewater; blanket gas; instrument and control gas; refrigerant; inert gas;and/or hydrocarbon recovery.

To provide fluid flow paths through the self-supporting structure in anadsorbent bed unit, valve assemblies may include poppet valves, whicheach may include a disk element connected to a stem element which can bepositioned within a bushing or valve guide. The stem element may beconnected to an actuating means, such as actuating means, which isconfigured to have the respective valve impart linear motion to therespective stem. As may be appreciated, the actuating means may beoperated independently for different steps in the method to activate asingle valve or a single actuating means may be utilized to control twoor more valves. Further, while the openings may be substantially similarin size, the openings and inlet valves for inlet manifolds may have asmaller diameter than those for outlet manifolds, given that the gasvolumes passing through the inlets may tend to be lower than productvolumes passing through the outlets. Further, while this configurationhas valve assemblies, the number and operation of the valves may vary(e.g., the number of valves) based on the specific cycle beingperformed.

In one or more embodiments, the rapid cycle swing adsorption method thatutilize the self-supporting structures in the present techniques mayinclude rapid cycle temperature swing adsorption (RCTSA) and/or rapidcycle pressure swing adsorption (RCPSA). For example, the total cycletimes may be less than 600 seconds, less than 300 seconds, preferablyless than 200 seconds, more preferably less than 90 seconds, and evenmore preferably less than 60 seconds.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrative embodiments are only preferred examples of the inventionand should not be taken as limiting the scope of the invention.

What is claimed is:
 1. A processing unit comprising: a housing formingan interior region; a self-supporting structure disposed within theinterior region, wherein the self-supporting structure has greater than50% by weight of an active material in the self-supporting structure,and wherein the self-supporting structure is an open-celled structureconfigured to provide one or more defined channels for fluid flow pathsthrough the self-supporting structure, and wherein the self-supportingstructure consists essentially of the active material and a silicabinder material; and a plurality of valves secured to the housing,wherein each of the plurality of valves is configured to control fluidflow along a flow path extending between the self-supporting structureand a location external to the housing; wherein the self-supportingstructure is formed by: creating a template for a self-supportingstructure; disposing a mixture within the template, wherein the mixturehas greater than 50% by weight of the active material in theself-supporting structure and the silica binder material; curing thecombination of the template and the mixture to form a self-supportingstructure that is maintains a solid form; and removing the template fromthe self-supporting structure, wherein the one or more defined channelsare based on the template.
 2. The processing unit of claim 1, whereinthe processing unit is a cyclical swing adsorbent bed unit configured toremove contaminants from a gaseous feed stream that passes through theone or more defined channels in the self-supporting structure.
 3. Theprocessing unit of claim 1, wherein the self-supporting structure hasgreater than 60% by weight of the active material in the self-supportingstructure.
 4. The processing unit of claim 1, wherein theself-supporting structure has greater than 70% by weight of the activematerial in the self-supporting structure.
 5. The processing unit ofclaim 1, wherein the processing unit further comprises a flowdistributor disposed between the self-supporting structure and theplurality of valves.
 6. The processing unit of claim 1, wherein thehousing is configured to maintain a pressure from 5 pounds per squareinch absolute (psia) and 1,400 psia.
 7. The processing unit of claim 1,wherein the self-supporting structure has a low thermal mass.
 8. Theprocessing unit of claim 1, wherein the one or more defined channelscomprise two or more channels that are substantially parallel.
 9. Theprocessing unit of claim 1, wherein the self-supporting structure has aplurality of pores formed in the active material by removing a pluralityof polyethylene spheres from the active material to form the pluralityof pores.